Stars don't just come in four colours, but you're right, there are four main colour categories we use to describe them! Here's a breakdown:

* Blue: These are the hottest stars, with surface temperatures exceeding 25,000 degrees Celsius. They're relatively rare and tend to be very massive. Examples: Rigel (Orion), Spica (Virgo)

* White: Stars with surface temperatures between 10,000 and 25,000 degrees Celsius. Our own sun falls into this category, although it appears yellow to us due to atmospheric scattering. Examples: Sirius (Canis Major), Vega (Lyra)

* Yellow: Stars with surface temperatures between 5,000 and 10,000 degrees Celsius. Examples: Sun, Procyon (Canis Minor), Alpha Centauri A

* Red: The coolest stars with surface temperatures below 3,500 degrees Celsius. They are much more common than their hotter counterparts. Examples: Betelgeuse (Orion), Antares (Scorpius)

It's important to remember that stars can be many shades within these categories. For example, some red stars can appear orange, and some white stars may have a slightly blueish hue.